SEW-Eurodrive MOVIPRO Ethernet/IP - Parameter Access Via Modbus;Tcp; Procedure with FC16 and FC03; Procedure with FC23

9
Modbus protocol (Modbus/TCP)
Parameter access via Modbus/TCP
Manual – MOVIPRO
®
with EtherNet/IP™ or Modbus/TCP Fieldbus Interface
110
9.4 Parameter access via Modbus/TCP
A parameter access via the MOVILINK
®
parameter channel in registers 200
hex
–203
hex
via Modbus/TCP requires the services FC03, FC16 or FC23 (write and read access).
Write access is used for storing acyclic requests in the corresponding registers. Read
services read the responses from the same registers.
This method corresponds to the alternative concept according to the Modbus specific-
ations "Network Messaging Specification for the MODBUS/TCP Protocol: Version
1.1" (Appendix A).
9.4.1 Procedure with FC16 and FC03
Master/
Modbus client
Slave/
Modbus server
FC16 request with
non-cyclical job
FC03 request to
read non-cyclical
result
FC16 response,
write access o.k.
FC03 response with
non-cyclical result
9007200887627659
An incorrect write access returns the corresponding error code. In this way the write
services are already processed by sending a write request (FC16), and the service
confirmation is carried out by evaluating the write response. Later on, the fieldbus
master will send a read request (FC03) in order to read out the values that have now
been written into the register. For more information about the error codes, see chapter
"Fault codes (exception codes)"(→2113).
9.4.2 Procedure with FC23
Master/
Modbus client
Slave/
Modbus server
FC23 request with
non-cyclical job
FC03 response with
non-cyclical result
9007200887695115
With FC23 the result is returned directly in the response.
16998413/EN – 12/2016